2D metal–organic networks based on asymmetric hexa-carboxylates and tetra-carboxylates ligands: A microporous Cl-pillared anionic bilayer and a neutral (4, 8)-net

•New asymmetric tetra-carboxylates and hexa-carboxylates ligands.•First bilayer MOF pillared by monatomic Cl linker.•Bilayer MOF exhibits true porosity.

New asymmetric tetra-carboxylates ligand, 2,2′-((6-chloro-1,3,5-triazine-2,4-diyl)bis(azanediyl))diterephthalic acid (H4L1) and hexa-carboxylates ligand, 2,2′,2″-((1,3,5-triazine-2,4,6-triyl)(azanediyl))-triterephthalic acid (H6L2), were designed and used for the assemble reactions with Cd2+ ions. [Cd2(L1)(H2O)2]·2.5DMSO·2H2O (1) and (Me2NH2)9(H3O)2[Cd2Cl3(L2)2]·5H2O (2) have been synthesized and structurally characterized. Single crystal X-ray analysis show that compound 1 bears a 2D neutral (4, 8)-net based on 3-connected {Cd2} nodes and 3-connected spacers. 2 is the first bilayer MOFs pillared by monatomic Cl linker and its structure is built of 4-connected single metal nodes and 3-connected spacers. The topology of the resulted (3, 4)-connected anionic framework could be described as (63)(66) (Schläfli symbol). N2 sorption isotherm of 2 shows typical type I behavior with BET surface area of 599 m2 g−1 and a micropore volume of 0.2345 cm3 g−1. Luminescent analysis indicates both compounds exhibit linker-localized emission. Furthermore, infrared (IR), thermogravimetric analyses (TGA) properties of the compounds were also investigated.

Graphical abstractThe assemble reactions of 3-connected asymmetric carboxylates ligands and Cd2+ ions led to a 2D neutral (4, 8)-net and a rare 2D Cl-pillared bilayer bearing (3, 4)-connected (63)(66) topology.Figure optionsDownload full-size imageDownload as PowerPoint slide